Integrated circuits may utilize dynamic voltage scaling and/or dynamic frequency scaling to reduce power consumption when full performance is not needed. Dynamic frequency scaling is a power management technique where the frequency of a microprocessor can be automatically adjusted. The frequency may be adjusted downwards to conserve power or may be adjusted upwards to increase performance. Similarly, dynamic voltage scaling is a power management technique where the voltage used in a microprocessor can be automatically adjusted. The voltage may be adjusted downwards to conserve power or may be adjusted upwards to increase performance.
Some systems may comprise more than one integrated circuit. These systems use a transport clock to transmit data between the devices. The frequency of the transport clock is fixed by a protocol. For example, a universal serial bus (USB) high speed interface is defined to operate using a transport clock having a frequency of 480 MHz. Although the operating frequency and/or voltage of the integrated circuits may be adjusted, the frequency or voltage requirements of the transport clock between integrated circuits are fixed.